If I were Google (or Twitter), I'd be satisfied with the competition-killing effects of publishing open APIs and shutting them down after a while, to the point of considering this an interesting defensive tactic. So much creative energy just dissipates instead of going into some possibly dangerous competing product...

Looks like Google has been shutting down features and apps that they think are not core to their business after the management shuffle and Page took over. And in their defense the announcement came pretty early.